I have known for a long time that sakura (cherry blossoms) are a really big deal in Japanese culture. I did not understand the fuss. I have seen cherry blossoms in San Francisco, and in Taiwan. They look nice, but not so much that I would throw a party just because the cherry trees are in bloom.
But there is an important different between San Francisco/Taiwan and Japan.
San Francisco and Taiwan are mostly subtropical/tropical.
Japan is mostly temperate.
I wanted to go hiking during my first Japan trip, but … ha ha … I was in Japan in winter, and I do not have the equipment/experience for hiking through deep snow. I did do some hiking in light snow, something I had never done before.
There was one mountain, Karakuni-dake (in Kirishima), which I really wanted to hike, but I did not want to hike it in the snow, so I waited until just around when I thought it would be snow free.
My timing was almost exactly correct. When I hiked Karakuni-dake, there was still some ice and snow patches, but the trail itself was essential snow/ice free.
And that just happened to be the day that cherry blossoms were erupting around Kirishima. In fact, they were the first cherry blossoms I saw in Japan.
Then it clicked for me.
I have experienced winter in southern Japan (with an escape to Okinawa prefecture), with modern conveniences such as indoor heating, and the inconvenience of constantly having to bundle myself to go outside in Kyoto.
Japanese people deal with much more severe winters than what I experienced, and they have done so for as long as Japanese culture has existed.
Sakura are a sign of spring. Sakura are a sign that the Japanese winter is over. That is a reason to throw a party.